Simple LC/MS Analysis of Carbohydrates

Introduction

There are many separation and detection methods are available for the determination of saccharides. These include GC-MS with derivatization, HPLC-UV with derivatization, HPAEC-PAD (High-performance anion-exchange chromatography coupled with pulsed amperometric detection), and LC-MS. The availability of a sensitive and accurate method is still a challenge. For an LC-MS method, given the high polarity, hydrophilicity and low proton affinity of these compounds, it can be difficult to ionize them directly by electrospray by ESI or APCI. The chemical diversity and numerous isomers of carbohydrates further complicates their analysis with LC-MS.

In this Application Note, post-column chloride attachment is used for the analysis of samples containing carbohydrates using the Advion expression Compact Mass spectrometer (CMS). The 35Cl and 37Cl isotopes also provide confirmation for the formation of the chloride adducts in negative ion APCI mode. Four carbohydrates (Fructose, Glucose, Sucrose and Lactose) are used for method verification.